1. Field of the Invention
The present invention relates to a linking method and a linking apparatus, and in particular, to a linking method and a linking apparatus enabling quick and accurate linking of knitted fabrics.
2. Description of the Prior Art
In a knitted fabric, a loose course is conventionally formed. The loose course consists of knitted loops which are larger than the other knitted loops (hereinafter, such large knitted loops are referred to simply as linking loops) such that the knitted fabric is linked to another knitted fabric to produce the defined size and shape of a product when the knitted loops are joined to each other by linking. When a knitted fabric is disposed on a linking apparatus, an operator stretches the knitted fabric with both hands so as to look through the knitted fabric to identify the linking loops which define a loose course. In this manner, the operator inserts a point needle through each of the linking loops defining the loose course.
This operation is performed in a similar manner for a tubular knitted fabric having a tubular shape. First, an operator puts his (her) hands into an opening of a tubular knitted fabric to laterally stretch the tubular knitted fabric so as to look through the knitted fabric on a far side when seen from the operator. In this manner, the operator identifies linking loops so as to insert a point needle of a linking apparatus through each of the linking loops.
Thereafter, the operator performs a similar operation for the knitted fabric on the operator side, thereby attaching the tubular knitted fabric to the linking apparatus.
However, it is extremely difficult to insert point needles through the linking loops because the linking loops are only slightly larger than normally knitted loops. For the tubular knitted fabric, in particular, after piercing point needles through a knitted fabric on the far side, it is difficult to stretch the knitted fabric on the operator side. Therefore, the difficulty of piercing with the point needles is increased.
As a result, the linking operation disadvantageously takes a long time to complete. Moreover, an inconvenience occurs in that point needles are withdrawn when linking of the loops is carried. Consequently, the yield of products is reduced.
In view of the problems described above, methods described in Japanese Patent Laid-Open Publication Nos. Hei. 11-207061 and 11-207062 have been developed. In the methods disclosed in the above-cited patent publications, it is necessary to insert a point needle through linking loops while one-by-one adjusting the positions of the point needles with respect to the linking loops in a linking operation because the linking loops are rarely placed at constant intervals. Moreover, in these methods, it is necessary to manually insert point needles through the linking loops provided on the edge of a knitted fabric because it is difficult to detect the linking loops provided in the vicinity of the edge of the knitted fabric. As a result, the amount of time required to complete the linking is increased, making it impossible to quickly perform the linking.
To overcome the problems described above, preferred embodiments of the present invention provide a linking method and a linking apparatus, which allow point needles to be quickly and accurately inserted through linking loops formed in a knitted fabric so as to enable tight and accurate linking of knitted fabrics.
A first preferred embodiment of the present invention provides a method for linking knitted fabrics, each having a loose course for linking, including the steps of opposing the knitted fabrics to be linked to each other, stretching the opposed knitted fabrics in a course direction, stretching the opposed knitted fabrics in a wale direction, picking up a multiple gray-scale image including an image of linking loops defining a loose course of each of the stretched knitted fabrics, performing an image processing on the multiple grayscale image so as to detect positions of the linking loops, inserting a point needle through each of the linking loops, sewing a linking loop in the vicinity of an edge of each of the knitted fabrics, and threading the linking loops other than the sewn linking loop by using the point needle inserted through the linking loop so as to link the knitted fabrics together.
In the first preferred embodiment, the linking loops in the vicinity of the edges of the knitted fabrics are quickly and accurate linked. The remaining linking loops are accurately threaded to perform the linking.
The step of sewing the linking loop in the vicinity of the edge of each of the knitted fabrics preferably involves threading one linking loop a plurality of times.
With this step, the linking loops in the vicinity of the edges of the knitted fabrics are more tightly linked.
The step of stretching the opposed knitted fabrics in the course direction includes piercing a plurality of needles through the knitted fabrics while the knitted fabrics are being stretched in the course direction so as to fix the knitted fabrics
With this step, the knitted fabrics in a stretched state become stable, thereby enabling more accurate linking.
The step of stretching the opposed knitted fabrics in the course direction according to the first preferred embodiment preferably further includes the steps of pinching the opposed knitted fabrics in a stretched state in the course direction, and piercing a plurality of needles through the knitted fabrics which are pinched in a stretched state so as to fix the knitted fabrics.
With these addition steps, the knitted fabrics in a stretched state is even more stable, thereby enabling more accurate linking.
The step of performing the image processing on the multiple gray-scale image so as to detect the positions of the linking loops according to the first preferred embodiment preferably includes detecting the positions of the linking loops by pattern matching.
With this step, large knitted loops formed immediately above or immediately below the loose course are not misrecognized as linking loops, thereby enabling more accurate linking.
The linking method according to the first preferred embodiment preferably further includes the step of placing a plate-like material between the opposed knitted fabrics, the plate-like material having a visual effect which allows clear visualization of a boundary between a knitted portion of the knitted fabric and a portion including no knitting yarn.
With this step, the positions of the linking loops is easily detected, thereby enabling more accurate linking.
The plate-like material preferably emits light, such that the positions of the linking loops are more easily detected, thereby enabling more accurate linking.
The knitted fabrics according to the first preferred embodiment preferably defined a tubular knitted fabric, and the step of opposing the knitted fabrics to be linked involves opposing the knitted fabrics to each other into a shape to be formed by linking the tubular knitted fabric, so as to quickly link the linking loops present in the vicinity of an edge of the tubular knitted fabric which is flattened or nearly flattened such that the knitted fabrics to be linked together are opposed to each other. Moreover, the remaining linking loops are accurately threaded to be linked together.
Each of the knitted fabrics according to the first preferred embodiment preferably includes a course formed to have a thin thickness, and the step of pinching the opposed knitted fabrics in the stretched state in the course direction involves pinching each of the knitted fabrics at the course formed to have the thin thickness, such that the knitted fabrics is easily and firmly pinched along the loose course so as to allow the loose course to be regularly arranged. As a result, accurate and quick linking is made possible.
Each of the knitted fabrics according to the first preferred embodiment preferably include a loose course formed in a vicinity of the course formed to have a thin thickness, and the step of pinching the opposed knitted fabrics in a stretched state in the course direction involves pulling a side of each of the knitted fabrics where the loose course is not formed in a state where the knitted fabrics at the course formed to have the thin thickness are pinched so as to arrange the loose course along an edge of a member pinching the knitted fabrics, such that the loose course is more regularly arranged, thereby enabling more accurate and quick linking.
A second preferred embodiment of the present invention provides a linking apparatus for linking knitted fabrics, each having a loose course for linking, including a course stretching device for stretching the knitted fabrics in a course direction in a state where the knitted fabrics are opposed to each other, a wale stretching device for stretching the opposed knitted fabrics in a wale direction, an image-pickup device for picking up a multiple gray-scale image including an image of linking loops constituting a loose course of each of the stretched knitted fabrics, a linking loop detection device for performing an image processing on the multiple gray-scale image so as to detect positions of the linking loops, a point needle insertion device for inserting a point needle through each of the linking loops, and a sewing machine mechanism for sewing a linking loop in a vicinity of an edge of each of the knitted fabrics and for threading the linking loops other than the sewn linking loop by using the point needle inserted through the linking loops to link the linking loops together.
With the linking apparatus according to the second preferred embodiment of the present invention, the linking loops present in the vicinity of an edge of the knitted fabric are quickly linked, whereas the remaining linking loops are accurately threaded to be linked together.
The sewing machine mechanism according to the second preferred embodiment threads the linking loop in the vicinity of the edge of each of the knitted fabrics for a plurality of times, such that the linking loops in the vicinity of the edges of the knitted fabrics are more tightly linked.
The course stretching device according to the second preferred embodiment is preferably defined by a plurality of needles piercing through the knitted fabrics while the knitted fabrics are being stretched in the course direction, such that the knitted fabrics in a stretched state become stable, thereby enabling more accurate linking.
The course stretching device according to the second preferred embodiment preferably further includes a pinching device for pinching the opposed knitted fabrics in a stretched state in the course direction, and a fixation device for piercing a plurality of needles through the knitted fabrics which are pinched in a stretched state so as to fix the knitted fabrics, such that the knitted fabrics in a stretched state become stable, thereby enabling more accurate linking.
The linking loop detection device according to the second preferred embodiment preferably detects the positions of the linking loops by pattern matching, such that large knitted loops formed immediately above or immediately below the loose course are not misrecognized as linking loops, thereby enabling more accurate linking.
The linking apparatus according to the second preferred embodiment of the present invention preferably further includes a plate-like material having a visual effect which allows clear visualization of a boundary between a knitted portion of the knitted fabric and a portion including no knitting yarn when the plate-like material is placed between the opposed knitted fabrics, such that the positions of the linking loops are easily detected, thereby enabling more accurate linking.
The plate-like material is preferably a light emitter. such that the positions of the linking loops are more easily detected, thereby enabling more accurate linking.
In this case, it is possible to quickly link the linking loops present in the vicinity of an edge of the tubular knitted fabric which is flattened or nearly flattened so that the knitted fabrics to be linked together are opposed to each other. Moreover, the remaining linking loops are accurately threaded to be linked together.
The knitted fabrics preferably define a tubular knitted fabric, and the course stretching device and the wale stretching device stretch the tubular knitted fabric while the knitted fabrics are being opposed to each other into a shape to be formed by linking the tubular knitted fabric.
In this case, the knitted fabrics can be easily and firmly pinched along the loose course so as to allow the loose course to be regularly arranged. As a result, accurate and quick linking is made possible.
Each of the knitted fabrics preferably includes a course having a thin thickness, and the pinching device for pinching the opposed knitted fabrics in the stretched state in the course direction pinches each of the knitted fabrics at the course having the thin thickness, such that the loose course is more regularly arranged, thereby enabling more accurate and quick linking.
Each of the knitted fabrics preferably includes a loose course formed in a vicinity of the course having the thin thickness, and the pinching device for pinching the opposed knitted fabrics in the stretched state in the course direction includes a pulling device for pulling a side of each of the knitted fabrics where the loose course is not formed in a state where the knitted fabrics at the course formed to have the thin thickness are pinched so as to arrange the loose course along an edge of the pinching device.
Other features, elements, advantages and characteristics of the present invention will become more apparent from the following detailed description of preferred embodiments thereof with reference to the attached drawings.